The present invention relates to a scanning electron microscope and, more particularly, to a scanning electron microscope having vibration resistance.
In a scanning electron microscope, a sample is scanned with an electron beam to generate a signal characteristic of the sample such as a secondary electron signal or a reflected electron signal from the sample. The generated signal is detected, and the detected signal is transmitted to a display as a brightness modulation signal. A screen of the display is scanned in synchronism with the scanning of the sample, and accordingly an image of the sample is displayed on the screen.
The scanning electron microscope has a sample movement device. Thereby, the sample can be moved in arbitrary directions on a plane perpendicular to the axis of the electron beam in the sample chamber, and can be also moved in an axial direction of the electron beam. Further, the sample can be rotated around the axis of the electron beam, and can be also tilted with respect to the axis of the electron beam.
When floor vibration or vibtation caused by sound is transmitted to the sample in the scanning electron microscope, the image is disturbed to decrease its resolution. Therefore, preventive measures against vibration have been usually taken, as described later. However, the measures are not always sufficient.
An object of the present invention is to provide a scanning electron microscope which can separate the sample from vibration and accordingly improve its resolution.
According to the present invention, a scanning electron microscope is provided which comprises a sample movement device for moving a sample, the sample movement device including a first table for moving the sample in a first direction, a second table for moving the sample in a second direction perpendicular to the first direction, a tilting table for supporting the first and second tables so as to afford tilting operation to the sample; an electron gun generating an electron beam, an axis of the electron beam being perpendicular to the first and second directions; a means for scanning the sample with the electron beam to generate a signal characteristic of the sample and detecting the generated signal; and a lock mechanism for locking the tilting table in a direction of the axis of the electron beam and in the first and second directions in a vibration-proof manner.
Other objects and features of the present invention will be become apparent from the descriptions of preferred embodiments of the present invention taken in connection with the accompanying drawings.